The present invention relates to a process for the dehumidification of moist air or saturated water vapour by an adiabatic absorption by means of a suitable absorption liquid above which the water vapour pressure is low.
The invention is especially useful in the drying of various materials, such as wood, cellulose, paper, peat, etc., but it may also be used e.g. in the dehumidification of air in public baths or municipal wastewater treatment plants. The following description will mainly relate to the use of the novel dehumidification process in connection with drying but the invention is not limited thereto.
The drying process is the most energy consuming of all the industrial processes comprising the separation or removal of a liquid from a solid substance. Mechanical separation methods, such as filtration, pressing, etc., are the least energy consuming methods, but also evaporation performed as multiple or flash evaporation requires much less energy than a drying process. The amount of energy consumed by multiple evaporation--expressed as the amount of steam consumed for the heating--is 0.2-0.5 tons of heating steam per ton of evaporated water; while a drying process will consume 1.2-2.2 tons of heating steam per ton of water removed.